This project proposes a comprehensive detailed review of the evaluation research on rehabilitation programs for offenders generally, focusing on drug treatment offered to offenders in all levels of criminal justice custody. It also focuses on the effects of various interventions on drug-using offenders where treatment for substance abuse was not necessarily the primary mission. This research will assemble, annotate, and analyze all studies conducted since 1968, i.e., since studies reported by Lipton, Martinson and Wilks in The Effectiveness of Correctional Treatment: A Survey of Treatment Evaluation Studies (1975). The general objectives are a) seek out all credible evaluation studies of treatment of offenders, drug abusing and non-drug abusing alike, b) examine and assemble them to inform policy and practice in the most meaningful way, and c) update the original survey and assess the effectiveness of correctional treatment at the current state of the art with particular focus on treatment for drug abusers. Specifically, the study will a) assess the impact of the various treatments on several outcome measures, particularly drug abuse and recidivism; b) describe the policy implications of the results for correctional treatment programming and future research; c) describe each of the modalities of criminal justice-based treatment for drug abuser- offenders in detail in terms of variety, clientele, staff, setting, duration, frequency, completeness of implementation, relationship to other concurrent and subsequent modalities, continuity of treatment, and outcome; d) describe and analyze each outcome criterion (e.g., relapse to drug use, recidivism, employment) in terms of variety, relative precision, relationship to other criteria, and utility for evaluations of correctional treatment for drug abusers; e) perform a variety of analyses including meta- analyses comparing 1) the absolute effect of each treatment on each of the outcome variables (for which data are available); 2) the relative effect effect sizes of all the treatments for each outcome variable; and 3) the effect sizes for different population subsets (e.g., genders, age and race groupings); f) assess the degree to which a variety of independent and moderator variables (e.g, treatment methods, program characteristics, client characteristics, research methodologies) have effects on outcomes; g) address the question-"what works?-and whether and how the conclusions have changed since the studies analyzed in The Effectiveness of Correctional Treatment: were completed, especially for drug abusing offenders; h) disseminate the findings widely to legislators, practitioners, and policy makers on "what works" in criminal justice based drug abuse treatment, and i) deposit the collection of documents in a publicly accessible library.